drivers/iio/health/max30100.c

   1 /*
   2  * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
   3  *
   4  * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * TODO: enable pulse length controls via device tree properties
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/delay.h>
  23 #include <linux/err.h>
  24 #include <linux/irq.h>
  25 #include <linux/i2c.h>
  26 #include <linux/mutex.h>
  27 #include <linux/of.h>
  28 #include <linux/regmap.h>
  29 #include <linux/iio/iio.h>
  30 #include <linux/iio/buffer.h>
  31 #include <linux/iio/kfifo_buf.h>
  32
  33 #define MAX30100_REGMAP_NAME    "max30100_regmap"
  34 #define MAX30100_DRV_NAME       "max30100"
  35
  36 #define MAX30100_REG_INT_STATUS                 0x00
  37 #define MAX30100_REG_INT_STATUS_PWR_RDY         BIT(0)
  38 #define MAX30100_REG_INT_STATUS_SPO2_RDY        BIT(4)
  39 #define MAX30100_REG_INT_STATUS_HR_RDY          BIT(5)
  40 #define MAX30100_REG_INT_STATUS_FIFO_RDY        BIT(7)
  41
  42 #define MAX30100_REG_INT_ENABLE                 0x01
  43 #define MAX30100_REG_INT_ENABLE_SPO2_EN         BIT(0)
  44 #define MAX30100_REG_INT_ENABLE_HR_EN           BIT(1)
  45 #define MAX30100_REG_INT_ENABLE_FIFO_EN         BIT(3)
  46 #define MAX30100_REG_INT_ENABLE_MASK            0xf0
  47 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT      4
  48
  49 #define MAX30100_REG_FIFO_WR_PTR                0x02
  50 #define MAX30100_REG_FIFO_OVR_CTR               0x03
  51 #define MAX30100_REG_FIFO_RD_PTR                0x04
  52 #define MAX30100_REG_FIFO_DATA                  0x05
  53 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT      16
  54 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN        4
  55
  56 #define MAX30100_REG_MODE_CONFIG                0x06
  57 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN   BIT(0)
  58 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN     BIT(1)
  59 #define MAX30100_REG_MODE_CONFIG_MODE_MASK      0x03
  60 #define MAX30100_REG_MODE_CONFIG_TEMP_EN        BIT(3)
  61 #define MAX30100_REG_MODE_CONFIG_PWR            BIT(7)
  62
  63 #define MAX30100_REG_SPO2_CONFIG                0x07
  64 #define MAX30100_REG_SPO2_CONFIG_100HZ          BIT(2)
  65 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN      BIT(6)
  66 #define MAX30100_REG_SPO2_CONFIG_1600US         0x3
  67
  68 #define MAX30100_REG_LED_CONFIG                 0x09
  69 #define MAX30100_REG_LED_CONFIG_LED_MASK        0x0f
  70 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT   4
  71
  72 #define MAX30100_REG_LED_CONFIG_24MA            0x07
  73 #define MAX30100_REG_LED_CONFIG_50MA            0x0f
  74
  75 #define MAX30100_REG_TEMP_INTEGER               0x16
  76 #define MAX30100_REG_TEMP_FRACTION              0x17
  77
  78 struct max30100_data {
  79         struct i2c_client *client;
  80         struct iio_dev *indio_dev;
  81         struct mutex lock;
  82         struct regmap *regmap;
  83
  84         __be16 buffer[2]; /* 2 16-bit channels */
  85 };
  86
  87 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
  88 {
  89         switch (reg) {
  90         case MAX30100_REG_INT_STATUS:
  91         case MAX30100_REG_MODE_CONFIG:
  92         case MAX30100_REG_FIFO_WR_PTR:
  93         case MAX30100_REG_FIFO_OVR_CTR:
  94         case MAX30100_REG_FIFO_RD_PTR:
  95         case MAX30100_REG_FIFO_DATA:
  96         case MAX30100_REG_TEMP_INTEGER:
  97         case MAX30100_REG_TEMP_FRACTION:
  98                 return true;
  99         default:
 100                 return false;
 101         }
 102 }
 103
 104 static const struct regmap_config max30100_regmap_config = {
 105         .name = MAX30100_REGMAP_NAME,
 106
 107         .reg_bits = 8,
 108         .val_bits = 8,
 109
 110         .max_register = MAX30100_REG_TEMP_FRACTION,
 111         .cache_type = REGCACHE_FLAT,
 112
 113         .volatile_reg = max30100_is_volatile_reg,
 114 };
 115
 116 static const unsigned int max30100_led_current_mapping[] = {
 117         4400, 7600, 11000, 14200, 17400,
 118         20800, 24000, 27100, 30600, 33800,
 119         37000, 40200, 43600, 46800, 50000
 120 };
 121
 122 static const unsigned long max30100_scan_masks[] = {0x3, 0};
 123
 124 static const struct iio_chan_spec max30100_channels[] = {
 125         {
 126                 .type = IIO_INTENSITY,
 127                 .channel2 = IIO_MOD_LIGHT_IR,
 128                 .modified = 1,
 129
 130                 .scan_index = 0,
 131                 .scan_type = {
 132                         .sign = 'u',
 133                         .realbits = 16,
 134                         .storagebits = 16,
 135                         .endianness = IIO_BE,
 136                 },
 137         },
 138         {
 139                 .type = IIO_INTENSITY,
 140                 .channel2 = IIO_MOD_LIGHT_RED,
 141                 .modified = 1,
 142
 143                 .scan_index = 1,
 144                 .scan_type = {
 145                         .sign = 'u',
 146                         .realbits = 16,
 147                         .storagebits = 16,
 148                         .endianness = IIO_BE,
 149                 },
 150         },
 151         {
 152                 .type = IIO_TEMP,
 153                 .info_mask_separate =
 154                         BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 155                 .scan_index = -1,
 156         },
 157 };
 158
 159 static int max30100_set_powermode(struct max30100_data *data, bool state)
 160 {
 161         return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 162                                   MAX30100_REG_MODE_CONFIG_PWR,
 163                                   state ? 0 : MAX30100_REG_MODE_CONFIG_PWR);
 164 }
 165
 166 static int max30100_clear_fifo(struct max30100_data *data)
 167 {
 168         int ret;
 169
 170         ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0);
 171         if (ret)
 172                 return ret;
 173
 174         ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0);
 175         if (ret)
 176                 return ret;
 177
 178         return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0);
 179 }
 180
 181 static int max30100_buffer_postenable(struct iio_dev *indio_dev)
 182 {
 183         struct max30100_data *data = iio_priv(indio_dev);
 184         int ret;
 185
 186         ret = max30100_set_powermode(data, true);
 187         if (ret)
 188                 return ret;
 189
 190         return max30100_clear_fifo(data);
 191 }
 192
 193 static int max30100_buffer_predisable(struct iio_dev *indio_dev)
 194 {
 195         struct max30100_data *data = iio_priv(indio_dev);
 196
 197         return max30100_set_powermode(data, false);
 198 }
 199
 200 static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
 201         .postenable = max30100_buffer_postenable,
 202         .predisable = max30100_buffer_predisable,
 203 };
 204
 205 static inline int max30100_fifo_count(struct max30100_data *data)
 206 {
 207         unsigned int val;
 208         int ret;
 209
 210         ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
 211         if (ret)
 212                 return ret;
 213
 214         /* FIFO is almost full */
 215         if (val & MAX30100_REG_INT_STATUS_FIFO_RDY)
 216                 return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1;
 217
 218         return 0;
 219 }
 220
 221 static int max30100_read_measurement(struct max30100_data *data)
 222 {
 223         int ret;
 224
 225         ret = i2c_smbus_read_i2c_block_data(data->client,
 226                                             MAX30100_REG_FIFO_DATA,
 227                                             MAX30100_REG_FIFO_DATA_ENTRY_LEN,
 228                                             (u8 *) &data->buffer);
 229
 230         return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret;
 231 }
 232
 233 static irqreturn_t max30100_interrupt_handler(int irq, void *private)
 234 {
 235         struct iio_dev *indio_dev = private;
 236         struct max30100_data *data = iio_priv(indio_dev);
 237         int ret, cnt = 0;
 238
 239         mutex_lock(&data->lock);
 240
 241         while (cnt || (cnt = max30100_fifo_count(data)) > 0) {
 242                 ret = max30100_read_measurement(data);
 243                 if (ret)
 244                         break;
 245
 246                 iio_push_to_buffers(data->indio_dev, data->buffer);
 247                 cnt--;
 248         }
 249
 250         mutex_unlock(&data->lock);
 251
 252         return IRQ_HANDLED;
 253 }
 254
 255 static int max30100_get_current_idx(unsigned int val, int *reg)
 256 {
 257         int idx;
 258
 259         /* LED turned off */
 260         if (val == 0) {
 261                 *reg = 0;
 262                 return 0;
 263         }
 264
 265         for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) {
 266                 if (max30100_led_current_mapping[idx] == val) {
 267                         *reg = idx + 1;
 268                         return 0;
 269                 }
 270         }
 271
 272         return -EINVAL;
 273 }
 274
 275 static int max30100_led_init(struct max30100_data *data)
 276 {
 277         struct device *dev = &data->client->dev;
 278         struct device_node *np = dev->of_node;
 279         unsigned int val[2];
 280         int reg, ret;
 281
 282         ret = of_property_read_u32_array(np, "maxim,led-current-microamp",
 283                                         (unsigned int *) &val, 2);
 284         if (ret) {
 285                 /* Default to 24 mA RED LED, 50 mA IR LED */
 286                 reg = (MAX30100_REG_LED_CONFIG_24MA <<
 287                         MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
 288                         MAX30100_REG_LED_CONFIG_50MA;
 289                 dev_warn(dev, "no led-current-microamp set");
 290
 291                 return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
 292         }
 293
 294         /* RED LED current */
 295         ret = max30100_get_current_idx(val[0], &reg);
 296         if (ret) {
 297                 dev_err(dev, "invalid RED current setting %d", val[0]);
 298                 return ret;
 299         }
 300
 301         ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
 302                 MAX30100_REG_LED_CONFIG_LED_MASK <<
 303                 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT,
 304                 reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT);
 305         if (ret)
 306                 return ret;
 307
 308         /* IR LED current */
 309         ret = max30100_get_current_idx(val[1], &reg);
 310         if (ret) {
 311                 dev_err(dev, "invalid IR current setting %d", val[1]);
 312                 return ret;
 313         }
 314
 315         return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
 316                 MAX30100_REG_LED_CONFIG_LED_MASK, reg);
 317 }
 318
 319 static int max30100_chip_init(struct max30100_data *data)
 320 {
 321         int ret;
 322
 323         /* setup LED current settings */
 324         ret = max30100_led_init(data);
 325         if (ret)
 326                 return ret;
 327
 328         /* enable hi-res SPO2 readings at 100Hz */
 329         ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
 330                                  MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
 331                                  MAX30100_REG_SPO2_CONFIG_100HZ);
 332         if (ret)
 333                 return ret;
 334
 335         /* enable SPO2 mode */
 336         ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 337                                  MAX30100_REG_MODE_CONFIG_MODE_MASK,
 338                                  MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
 339                                  MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
 340         if (ret)
 341                 return ret;
 342
 343         /* enable FIFO interrupt */
 344         return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
 345                                  MAX30100_REG_INT_ENABLE_MASK,
 346                                  MAX30100_REG_INT_ENABLE_FIFO_EN
 347                                  << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
 348 }
 349
 350 static int max30100_read_temp(struct max30100_data *data, int *val)
 351 {
 352         int ret;
 353         unsigned int reg;
 354
 355         ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, &reg);
 356         if (ret < 0)
 357                 return ret;
 358         *val = reg << 4;
 359
 360         ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, &reg);
 361         if (ret < 0)
 362                 return ret;
 363
 364         *val |= reg & 0xf;
 365         *val = sign_extend32(*val, 11);
 366
 367         return 0;
 368 }
 369
 370 static int max30100_get_temp(struct max30100_data *data, int *val)
 371 {
 372         int ret;
 373
 374         /* start acquisition */
 375         ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 376                                  MAX30100_REG_MODE_CONFIG_TEMP_EN,
 377                                  MAX30100_REG_MODE_CONFIG_TEMP_EN);
 378         if (ret)
 379                 return ret;
 380
 381         msleep(35);
 382
 383         return max30100_read_temp(data, val);
 384 }
 385
 386 static int max30100_read_raw(struct iio_dev *indio_dev,
 387                              struct iio_chan_spec const *chan,
 388                              int *val, int *val2, long mask)
 389 {
 390         struct max30100_data *data = iio_priv(indio_dev);
 391         int ret = -EINVAL;
 392
 393         switch (mask) {
 394         case IIO_CHAN_INFO_RAW:
 395                 /*
 396                  * Temperature reading can only be acquired while engine
 397                  * is running
 398                  */
 399                 mutex_lock(&indio_dev->mlock);
 400
 401                 if (!iio_buffer_enabled(indio_dev))
 402                         ret = -EAGAIN;
 403                 else {
 404                         ret = max30100_get_temp(data, val);
 405                         if (!ret)
 406                                 ret = IIO_VAL_INT;
 407
 408                 }
 409
 410                 mutex_unlock(&indio_dev->mlock);
 411                 break;
 412         case IIO_CHAN_INFO_SCALE:
 413                 *val = 1;  /* 0.0625 */
 414                 *val2 = 16;
 415                 ret = IIO_VAL_FRACTIONAL;
 416                 break;
 417         }
 418
 419         return ret;
 420 }
 421
 422 static const struct iio_info max30100_info = {
 423         .read_raw = max30100_read_raw,
 424 };
 425
 426 static int max30100_probe(struct i2c_client *client,
 427                           const struct i2c_device_id *id)
 428 {
 429         struct max30100_data *data;
 430         struct iio_buffer *buffer;
 431         struct iio_dev *indio_dev;
 432         int ret;
 433
 434         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 435         if (!indio_dev)
 436                 return -ENOMEM;
 437
 438         buffer = devm_iio_kfifo_allocate(&client->dev);
 439         if (!buffer)
 440                 return -ENOMEM;
 441
 442         iio_device_attach_buffer(indio_dev, buffer);
 443
 444         indio_dev->name = MAX30100_DRV_NAME;
 445         indio_dev->channels = max30100_channels;
 446         indio_dev->info = &max30100_info;
 447         indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
 448         indio_dev->available_scan_masks = max30100_scan_masks;
 449         indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
 450         indio_dev->setup_ops = &max30100_buffer_setup_ops;
 451         indio_dev->dev.parent = &client->dev;
 452
 453         data = iio_priv(indio_dev);
 454         data->indio_dev = indio_dev;
 455         data->client = client;
 456
 457         mutex_init(&data->lock);
 458         i2c_set_clientdata(client, indio_dev);
 459
 460         data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
 461         if (IS_ERR(data->regmap)) {
 462                 dev_err(&client->dev, "regmap initialization failed.\n");
 463                 return PTR_ERR(data->regmap);
 464         }
 465         max30100_set_powermode(data, false);
 466
 467         ret = max30100_chip_init(data);
 468         if (ret)
 469                 return ret;
 470
 471         if (client->irq <= 0) {
 472                 dev_err(&client->dev, "no valid irq defined\n");
 473                 return -EINVAL;
 474         }
 475         ret = devm_request_threaded_irq(&client->dev, client->irq,
 476                                         NULL, max30100_interrupt_handler,
 477                                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 478                                         "max30100_irq", indio_dev);
 479         if (ret) {
 480                 dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
 481                 return ret;
 482         }
 483
 484         return iio_device_register(indio_dev);
 485 }
 486
 487 static int max30100_remove(struct i2c_client *client)
 488 {
 489         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 490         struct max30100_data *data = iio_priv(indio_dev);
 491
 492         iio_device_unregister(indio_dev);
 493         max30100_set_powermode(data, false);
 494
 495         return 0;
 496 }
 497
 498 static const struct i2c_device_id max30100_id[] = {
 499         { "max30100", 0 },
 500         {}
 501 };
 502 MODULE_DEVICE_TABLE(i2c, max30100_id);
 503
 504 static const struct of_device_id max30100_dt_ids[] = {
 505         { .compatible = "maxim,max30100" },
 506         { }
 507 };
 508 MODULE_DEVICE_TABLE(of, max30100_dt_ids);
 509
 510 static struct i2c_driver max30100_driver = {
 511         .driver = {
 512                 .name   = MAX30100_DRV_NAME,
 513                 .of_match_table = of_match_ptr(max30100_dt_ids),
 514         },
 515         .probe          = max30100_probe,
 516         .remove         = max30100_remove,
 517         .id_table       = max30100_id,
 518 };
 519 module_i2c_driver(max30100_driver);
 520
 521 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 522 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
 523 MODULE_LICENSE("GPL");